1. Field of the Invention
The present invention relates to unique compositions including a bio-compatible oil and a non-steroidal anti-inflammatory drugs (NSAID), where the oil or a constituent thereof is effective in reducing GI toxicity of the NSAID and enhancing the drugs' therapeutic activity to treat inflammation, pain, fever and thrombosis as well as other diseases such as; stroke, traumatic brain injury, spinal chord injury, cardiovascular disease, ovarian cancer, colon cancer, Alzheimer's disease, arthritis, uveitis, and mucositis.
More particularly, the present invention relates to formulations in which a NSAID is admixed as a powder directly into a bio-compatible oil including a phospholipid to form a medication which can be a solution, a paste, a semi-solid, a dispersion, a suspension, a colloidal or mixtures thereof, where the medication can be administered internally, orally and/or topically.
2. Description of the Related Art
NSAIDs constitute a family of compounds, the first of which to be discovered being aspirin, that have the capacity to inhibit a number of biological pathogenic processes including; fever, inflammation, pain, thrombosis and carcinogenesis.1 As a direct consequence of their great therapeutic potential, NSAIDs are heavily consumed among the world's populace as both over-the-counter and prescription drugs. Because of their great utility, a significant percentage of our populace consume NSAIDs with regularity including: the 30-40 millions Americans who are afflicted with rheumatoid or osteoarthritis; and countless others that take the medication to treat/prevent: inflammation and pain caused by other inflammatory conditions or injury, the pain of dysmenorrhea; fever; the development of thrombosis and related cardiovascular diseases; ovarian cancer, colon cancer and Alzheimer's Disease.1,2 The problem with the trend of ever-increasing NSAID usage, especially among the elderly, is that these drugs commonly induce gastrointestinal (GI) side-effects.3-6 
In the stomach and small intestine the drugs cause dyspepsia (gastric distress, heartburn, bloating or nausea), erosions, gastritis/duodenitis and ulcers in some individuals. Gastrointestinal bleeding may also occur in NSAID users that can result in episodes of anemia (of variable severity), or hemorrhage—that may be life-threatening, in the most serious cases.7,8 One or more of these GI complications have been estimated to occur in 20-40% of regular NSAID users. Given the large NSAID market, even infrequent GI complications send an estimated 76,000 Americans to the hospital and kill estimated 7,600 annually.
One of the major contributions to the understanding of NSAID action came from the pioneering studies of Vane and associates in the early 1970's that reported that chemically dissimilar members of the NSAID family share the ability to inhibit the activity of the enzyme, cyclooxgenase (COX) that catalyzes the conversion of arachidonic acid to prostaglandin G2 and H2 by sequential steps of oxidation and peroxidation.9-11 Prostaglandin H2 will then be converted to one of several eicosanoids in a target cell by a process catalyzed by specific prostaglandin synthases. Thus, by reversibly or irreversibly inhibiting COX activity, NSAIDs could deplete a particular tissue or cellular fluid of prostaglandins, which has been demonstrated to promote tissue inflammation.12 Shortly after these revelations, Robert and his associates at the Upjohn Company demonstrated that certain classes of prostaglandins shared the remarkable property of protecting the GI epithelium from a number of ulcerogenic compounds and/or conditions, demonstrating the “cytoprotective” nature of these lipid mediators.13 Based upon these two major contributions, it was concluded that NSAIDs induce injury and ulceration to the GI epithelium by inhibiting mucosal COX activity and depleting the tissue of “cytoprotective” prostaglandins.
The next and most recent development in our understanding of arachidonic metabolism came in the early 1990's, when a number of investigators14-18 identified and cloned a second COX isozyme (now called COX-2), that was structurally and functionally related to the originally described enzyme (now called COX-1). In contrast to COX-1, which is constitutively expressed in most tissues including the GI mucosa, COX-2 was demonstrated to be inducible, primarily by cytokines and other mediators of inflammation. Based on these findings, together with evidence that COX-2 is selectively expressed at sites of inflammation, and is expressed at low or undetectable levels in non-inflamed GI mucosa,19-23 a number of pharmaceutical houses initiated the development of compounds that selectively inhibited COX-2.
This effort culminated in the launching of the first two COX-2 selective inhibitors, Celebrex (Celecoxib) and Vioxx (Rofecoxib). The pre-clinical and clinical data released to date have indicated that these compounds are therapeutically effective and have a low toxicity to the GI mucosa. This news has led to great excitement in both the medical and lay communities, which has translated into record number prescriptions of Celebrex and Vioxx being filled the first two years these drugs were on the market.24 
A major concern of the inventor and a number of other investigators studying NSAID-induced GI injury, is that the linkage between COX inhibition and GI injury and bleeding is not very strong. For example, Ligumsky and associates in the early 1980's published a series of papers in rats and dogs that appeared to dissociate COX inhibition from mucosal injury.25-27 Initially they demonstrated that the aspirin and its metabolite, salicylic acid had equivalent ability to induce injury to the canine gastric mucosa, even though aspirin depleted the tissue of “cytoprotective” prostaglandins, whereas salicylic acid displayed no COX inhibitory activity.25 In subsequent rodent studies, it was demonstrated that mucosal COX activity was inhibited by >90% regardless if aspirin was administered subcutaneously or intragastrically, although ulcerations only formed in the stomachs of rats when the NSAID was administered intragastrically.26,27 Whittle also reported a dissociation between indomethacin's effect to induce COX inhibition and mucosal injury in the small intestine, as intestinal lesions only begin to develop 48 hrs after NSAID administration, at a time point where COX activity (which is fully inhibited<3 hrs, post-indomethacin) has returned to normal.28 
It should be pointed out that the evidence suggesting that mucosal COX inhibition may not be directly involved in the pathogenesis of NSAID—induced enteropathy—is also supported by some clinical studies, which have reported that i.v. administration of aspirin did not cause detectable histological injury to the human gastric mucosa, in contrast to oral administration of the NSAID.29 It was also reported that after 2-4 weeks of NSAID treatment the human gastric mucosa becomes resistant to the injurious actions of oral aspirin or indomethacin, and that this adaptive response is not linked to a recovery of COX activity which remains fully blocked during the study period.30 
Lastly, the hypothesis that NSAIDs induce GI injury, primarily by inhibiting mucosal COX-1 predicts that mice deficient in the isozyme, due to targeted gene disruption, would be prone to the development of spontaneous mucosal ulcers and be more sensitive to NSAIDs than their wild type littermates. Langenbach and associates31 have reported that COX-1 null animals have no detectable GI disease and if anything are more resistant to indomethacin—induced ulcer development. To make matters more confusing, Morham et al.32 have reported in a subsequent study that COX-2 knockout mice are not viable and frequently succumb to peritonitis as well as renal disease. The possibility that COX-2 inhibition may be detrimental, has also been supported by a number of animal studies that indicate that the healing of ulcers in the proximal and distal gut is exacerbated if animals are treated with selective COX-2 blockers.33, 34 Similar complications in humans have not been reported to date.
Based on the evidence documented above, a compelling case can be made to investigate, other mechanisms by which NSAIDs may induce GI mucosal injury, and how this information can be used in the development of alternative strategies to reduce or prevent the GI toxicity of these compounds. Other potential targets of NSAID—induced gastro-enteropathy—are the ability of these drugs to: reduce mucosal blood flow and induce leukocyte adherence to the vascular wall; uncouple oxidative phosphorylation; induce cellular acidification due to their protonophore characteristics; and to attenuate the hydrophobic, non-wettable characteristics of the mucosa, thereby increasing the tissue's susceptibility to luminal acid.35-40 It is this latter property which has been the focus of the inventor's laboratory over the past 15-20 years.
In 1983, the inventor's laboratory made the initial observation that canine gastric mucosa had a uniquely hydrophobic surface, as determined by contact angle analysis.41, 42 Since then his and other laboratories have demonstrated that this non-wettable surface property of the gastric mucosa is found in a number of other species including rodents and man.40,43,44 Furthermore, both biochemical and morphological techniques were employed to demonstrate that this property may be attributable to an extracellular lining of surfactant-like phospholipid within and coating the mucus gel layer.45-47 The inventor's laboratory also observed that many agents that damage the gastric mucosa, including NSAIDs, have the capacity to rapidly transform the tissue from a non-wettable (hydrophobic) to a wettable (hydrophilic) state, and that this injurious action could be attenuated by the administration of synthetic or purified phospholipids.48-51 
In recent years, research has focused on the mechanism of NSAID—phospholipid interaction. In these studies, the inventor's laboratory have obtained compelling evidence that NSAIDs may induce mucosal injury by chemically associating with the zwitterionic phospholipids, such as phosphatidylcholine (PC) within and on the surface of the mucus gel layer, with the site of electrostatic binding being between the positively-charged choline head group of zwitterionic phospholipid, phosphatidylcholine (PC) and the negatively charged (carboxyl or sulfonyl) group of the NSAID.52 Based upon this information, our group evaluated the GI toxicity of a number of NSAIDs that were chemically pre-associated with synthetic or purified PC, prior to administration, and obtained evidence that these novel drugs were far less injurious, with regards to GI lesion formation and bleeding than the unmodified NSAIDs, in the rat. The applicability of this approach to human disease was recently confirmed when pilot clinical studies revealed that PC—aspirin, employing purified (93% pure) PC, induced significantly fewer gastric lesions in human subjects than unmodified aspirin over a 4 day period, in a pilot double blind, cross-over study.53 
Interestingly, the inventor's laboratory also determined that PC-NSAIDs have superior therapeutic efficacy and potency to the unmodified drugs in animal models of fever, inflammation/pain, thrombosis and osteoporosis indicating that their lower gastric toxicity could not be simply explained by a reduction in bioavailability.52,54 
Although the combination of PC (other of similar phospholipids) and NSAIDs result in reduced pathogenic effects of NSAID administration, oral administration of these combinations have been less than adequate because the combination requires a larger volume per effective dose than NSAID alone. Thus, there is a need in the art for a composition of NSAID and carrier that allows for increased NSAID concentration in the composition and where the carrier reduces the pathogenic effects of NSAIDs and is in a form that is amenable to administration orally, internally or topically. Moreover, there is a need in the art for an NSAID composition which has improved self-life, especially for aspirin-containing medicaments.